Brake for electric-motor-operated hoists



July 17, 1923- 1,462,265

M. COSULICH BRAKE FOR ELECTRIC MoTo OPERATED HOISTS Filed Oct. 27 #1921 Illlilillll Illlll!! INI 5 vwenlfoz Nazis@ @mmh atroz-M1113 MATTEO oosnLroH, or Nnvv` YORK, N. Y., AssrGNon 'ro kTrier/rasa BUCKLEY stares; Farrar for;

Herstr- ING oo., or NEW YORK, N. Y., A Conroe-Arron or Nnw Yoan.

BRAKE nonl nLnoTRIc-MoroR-ornnarnn Horsrs.

Application ined october 27, `i921. rske'raiNo.510,703;

To all whomz't may concern.'

Be it known that I, MATTEO CosULroH, a citizen'of thev United States, and resident of the borough of Manhattan7 city, county and State' of N ew York, have invented certain new and useful Improvements in Brakes for Electric-Motor-Operated Hoists, of which the following is a specification.

This invention relates to improvements in automatically acting 'brakes for electric-mo-- tor-operated hoisting` apparatus designed to prevent dropping of the load when the m04 tor circuit is broken.

As is well known, the armature shaft of'y an electric motor is free to lrotate ineither directionwhen the motor circuit is broken, and it is therefore necessary in electricmotor-driven hoists to providemeans for preventing the' pull of the load on the hoisting cable from unwinding the cable from the drum whenthe motor is stopped after the load has beenelevated to the desired point, or when the circuit is broken from any other cause, such' as' the blowing of'a fuse.Vv l l The object of the present invention is to provide a simple, efficient, and quick-acting brake whichv will automatically release the motor shaft and )permit it to lfreely rotate when current is supplied to the motor to raise a load, and which will instantly lock the motor shaft yif said shaft should start to rotate in the reverse direction In the drawing:

Figure 1 is a fragmentary side elevation of a well-known type of electric-motor-operated hoisting apparatus provided with the improved automatic. brake;

Fig. 2 is a side elevation of the brake mechanism;

Fig. 3 a section on the line 3-3 of Fig. 2;

Fig. 4 an edge view of the upper end I of the standard on which the brake-shoes are supported;

Figs. 5 and 6 perspective views of the two links which connect each shoe withthe sup porting standard and Fig. 7 a detail view showing the innerface of one of the brake shoes.

Referring to the drawing by numerals 1 designates the electric motor upon the armature shaft 2 ofwhich is fixed a pulley 3, said pulley being connected by a belt 4 with a pulley 5 on a counter shaft 6. A pinion 7 on shaft 6 meshes with a rear 8 on a shaft st-ood' that the usual drum-releasing clutch 95 andthe' hoisting' drum 10 upon which the hoisting cable' l1fis wound is also mounted on'shaft 9.y The foregoing parts constitute part'of arwell known form of-electric motor drivenfhoisting apparatus. It willr be undernot shown, is provided for perinittiuoi lowering of the hoisting tackley by gravit and it will also be obvious that the improved brake may be applied to other `types of electric `motor' driven hoists'than the one shown. 'n

The outer end of the armature shaft 2 of themotor lis journalledvin a bearing in the head 14 of a standard 15, which standardis rigidly held by bolts 16 to the bed 17 of the hoisting apparatus-` A suitable bushing 1K8 surrounds shaft 2 within the head 14. Theexterior of head 14 is of general cy-KVV lindrical bilged form, and a brake drum 12'` is held to shaft 2,adjacent vthe inner end of said head by a key 13. The dru1n`12 has a circumferential flange l9 overhanging head 14, the internal friction surface of` shaft 2 and they drum. f v p A pair of segmental brake` shoes 20,l prefwhich fdange is concentric withthe axis of erably `having their contactfaces coverel l i with a suitable friction material. 21, are shift-ably held to the Vhead 14 withinthe drum,` the outer contact faces of said slices being curved on the same'y arcV as the inner faceof `the kiai'igel ofthe drum. Each shoe 2O issupported by a pair of parallel links 22 and 23, theouter ends of Said links engaging in recesses 25 inthe inner'face of the shoe and being pivotally held to the shoe by pins 24having a tight ydriving fit in apertures 32 in the shoe and' extending loosely through apertures 33 in the links. The in-k v ner ends of the links engage in recesses 26 in the head 14 of standard 15 and are piv-A o tally held to said head byl pins 2K7 having a tight driving fit irl-apertures 34 in the head and extending loosely through apertures 85 in the links.

The twobrake shoes engage theflange 195 at diametrically opposed points,and the pair of. links supporting one of the Shoes extend downwardly and outwardly from one side of head 14 while the pair of links supporting the other shoe extend upwardly and out-L wardly from the head; Thedrum l2 rotates inthe direction indicated by the arrow in Fig. 2 when the motor is energized to elevate a load, and coil Springs `28 engaged in recesses 29 in projections 30 on links 22 and in recesses 31 in head 11i normally swing the links about the pivot pins 27 in the opposite direction, thereby yieldably urging the brake shoes 2O substantially radially out-ward against the internal surface of the flange 19of the brakedruin.

lt will be obvious that when current is supplied to motor 1 to cause cable 11 to be wound upon the hoisting` drurnlO and lift a load, the brake druin 12 will be free to rotate in the direction indicated by the arrow in F 2, assprings 28 will yield and only hold the shoes 20-21 inlight frictional en-k gagement with iiange 1.9 of the brake druin. lf, however, the niotor circuit is broken, the pull of the load on cable 1l will start to rotate inotor shaft 2 and the brake druin 12 in the reverse direction, whereupon springs 28 and the frictional contact of the druni flange 19Y with shoes 2O will rock the links about pivots 27 in a counter clockwise direction and cause the shoes to move radially outn ward and bind tightly against the inner surface of flange 19. rlihe reverse rotation of thedrum w'll thus ce stopped alrnost instantly as a very slight Voutward movement Voi the `brake slices will cause the same to exert a powerful braking action on the drum. The stopping of the brake drum l2 and shaft 2 will, of course, prevent further unwinding of the cable 1l as the hoisting drum 10 is geared up with shaft 2.

rEhe brake shoes engage the brake drum at substantially diainetrically points and the thrust from these shoesiwhen they engage lthe brake drum., is in opposite directions directly against the armature shaft bearing and is therefore coinoletel balanced. This is quite essential in apparat-us of this kind. The armature inust run true and all lateral thrust on the armature bearings and on the armature shaft must be oppositey either avoided or completely 4balanced in order that the armature shaft shall be maintained in proper alignment. Electrically operated hoisting apparatus is subject to very hard usage and the arinature shaft would soon be out of true alignment unless the sudden shocks and stresses due to the automatic operation of the armature lock or brake are not balanced or neutralized.

It will be evident that the load will be arrested after a very slight downward yinovenient thereof and before it acquires any nioinentuin, thus avoiding injurious shocks to the hoisting apparatus.l Slippingr will be impossible, even with very heavy loads, since the greater the weight ofthe load the tighter the shoes will be forced outward against the flange 19' of the brake drinn.

What l claim is:

an electric inotor operated hoisting apparatus, the combination of a brake drum fixed on the armature shaft and having an internal braking surface concentric with the shaft, two brake shoes within the druin and arranged to engage the drurn A,at diametrically opposite points, a stationary support forming a bearing for the armature shaft, a pair of outwardly extending links within the drum at each side ofthe said support one link of each pair being tangential, means pivotally connecting the inner ends of the links of each pair to said support at opposite sides thereof, means pivotally corr nectin'g a brake shoe with the outer ends of the links of each pair, and spring means normally tending to swing the links in one direction to bring the brake shoes into engagement with the brake drinn, whereby the thrust of the brake shoes will be in opposite directions and will be' balanced on the said` bearing support. f

In testimony whereof .T ,hereunto aflix my signature. p n

MATTEU COWSULICH. 

